LAGOS (AA) – Nigerian authorities on Thursday confirmed the 11th Ebola infection to be recorded in Africa’s most populous country.

“One of the doctors who attended to Mr. Patrick Sawyer has fallen ill and has now been quarantined,” Health Minister Onyebuchi Chukwu told reporters at a news briefing on the outbreak.

Ebola, a contagious disease for which there is no known treatment or cure, is believed to have arrived in Nigeria through Sawyer, an infected Liberian who came to the country in July.

After showing symptoms of Ebola, Sawyer was admitted to a Lagos hospital where he later succumbed to the virus.

The tropical fever, which first appeared in 1976 in Sudan and the Democratic Republic of Congo, can be transmitted to humans from wild animals.

It also reportedly spreads through contact with the body fluids of infected persons or of those who have died of the disease.

Minister Chukwu said some of those quarantined after showing Ebola symptoms were “doing very well and showing signs of recovery.”

He also announced that a nurse who escaped from a watch list and traveled to the eastern part of the country had been brought back to Lagos – along with at least 20 others with whom she had come in contact.

“All of them – the nurse, her husband and others – have been brought to Lagos,” the minister said.

Along with the other 20 from southeastern Enugu, 198 people – suspected of possible infection – are now under observation in Nigeria.

Three deaths have been confirmed so far, including two people who had come in contact with the Liberian.

But an online newspaper, Sahara Reporters, claimed that another nurse has died today in Lagos.

The health minister, for his part, did not confirm the report.

Lagos authorities did not respond to Anadolu Agency’s requests for comment on the reported new death.

It is the first time Nigeria has seen an Ebola outbreak since the discovery of the virus in 1976.

President Goodluck Jonathan has declared a state of national emergency in an effort to halt its spread, backed by $1.6 million for a raft of preventative measures.

At the moment, the virus is thought to be restricted to Lagos – a city notorious for its lack of sanitation and a transportation system that caters to some 20 million residents.